Method of making radiator elements



' March 21, 1933. 'F. K. HOF FMAN METHOD OF MAKING RADIATOR ELEMENTS Filed April 19, 1930 fi ma Patented Mar. 21, 1933 I i v l I UNITED STATES PATENT," orrlcs Application filed April 19, 1930. Serial No. 445,738.

This invention relates to the manufacture nated a shaping roll mounted opposite the of radiators, and more particularly to a -new median line of the pair of rollslO-lO to coand improved method for producing tubular operate therewith, on a column or post 13.

' heat transfer elements of radiators equipped This column 13 has ahori'zontal extension 14,

a with transverse radial fins spaced apart along which is slidably fitted on rests 1515, as 55 the length of the tubular radiator structure. shown with interposed antifriction rollersv My improved method consists in subjecting 15a. The rests 15 are shown as fixed in tubular stock, which may be initially a plain spaced apart relation upon a base plate 16, tube of suitable ductile metal such as alumiwhich constitutes a portion of a carriage num, copper, or the like, to the action of coadapted to slide on ways of-a usual or suitoperative rolls which, acting" radially and I able lathe having for this purpose bearing oppositely upon the tube externally thereof, blocks 17 to fit the ways of such lathe. The produce the requisite spaced-apart radiating horizontal extension 14 bears at its end opfinformations thereon by a rolling and spin posite the'column 13 another column or'post ning operation which has the eff ct of con- 18 equipped with an inner face'18a which is densing and strengthening the metal and engaged by a cam 19 mounted on a suitable making the rolled or spun fins particularly operating shaft 20. This cam also engages strong and resistant to pressures and strains. a face 11a on the column 11 so that the action In accordance with the method of myinvenof such cam is adapted to press the pair of tion, no form or guide interior of the tube is roll 10710 and the roll 12 towards each required but all of the operative action to other and against the tubular stock T which which the tube is subjected is applied exis suitably mounted on the lathe centers in teriorly thereof. The distinctive features Operative relation between said rolls. A tenand advantages of the invention will be betsion coil, spring 21 is itted to o-act bet en ter understood from the following detailed he faces 11a, 1861 tending to move the coldescription taken in conne tion with th a umns 11,18 so as toseparate the roll 12 from companying drawing and the features of the pair of rolls-1 O-10. It is to benoted that novelty will be thereafter pointed out in the sp ading r 118 are formed with a the appended claim. blunt V-shaped peripherywhile the shaping Referring to the drawing; Figure 1 is a roll 12 has a thicker'rounded periphery 12a. diagrammatic fragmentary elevation showand has associated therewith at the side ing the initial portion of the rolling or spinthereof a e n ary Hf iQIL 2 W i h ning operation as carried out by the rolls maybe designated as a guiding" roll. The

g upon the tube in accordance with my inven function of the spreading rolls 10 With their tion. Figure 2 is a similar view illustratin relatively narrower pperative edges is to of 85 the completion of the rolling operation upon feet a preliminary indentation of the metal a portion of th tub by whi h fin a d adin a narrower area, thus preparing the way jacent valley on'the tube is completed, and for the action of the wider shaping roll 40 Figure 3 is a partialend view with portions whlch determines the finished contour of the broken away and in section illustrating the finned tube. The T0118 10, 12 thus co-operate movements of the rolls which act upon the to eifect a spinning action upon the metal in 'tube. T indicates a portion of tubular stock a, manner that is particularlyefi'ective for which is provided of the requisite diameter the designed purpose. Between the shaping and length .in accordance with the dimension roll 12 and the guiding roll 22 is an abrupt of the radiator element to be produced. 10 andrelatively deep V- shaped valley 23 which 10 i di t a p ir of rolls --which may be. serves to determine the shape and contour of designated spreading rolls mounted in vertithe fins F which are produced by the rolling cal spaced apart relation on a column or post [operation upon the tube. It will be thus 50 11. 12'indicates a roll which may be desigunderstood that the depth and contour chary from the tube at acter of the fins F may be varied at will by a selection of rolls 10 and 12-22 according to the requirements of the work in hand, and in connection with a selectivelyvariable inward or feed movementof the rolls upon the tube as effected by cam 19 which may also be selectively changed in contour according to the requirements of the particular work.

It will be understood that in practice the carriage structure 16-17 is held stationary on the lathe bed while the rolls are performing the operation as described of producing each single fin and adjacent valley upon the tube, and that between such operations the camshaft 20 is operated by .suitable mecha: nism to permit retraction of the rolls away which time the roll bearing carriage by suitable mechanism is moved along the lathe ways a distance just sufficient to position the rollsfor producing the next ments into operating engagement therewith with operative portlons of said elements adapted to engage the metal of. the tube in a relatively narrower area at one side thereof and in a wider area producing the finished contour of the tubular finned element at another side thereof.

In witness whereof I have aflixed my name to this specification.

FRANK K. HOFFMAN.

-. fin on the tube, and that thissequence of opthe original tube erations may be continued indefinitely to produce any required length of tubular radiator product in accordance with my invention.- It is to be noted that the described operation results in increasing the length and diameter of the product as compared with thereof to create fins of any required shape or diameter, and to provide fluid chambers extending outward into the bases of the fins as seen in Figure 2.

An important advantage of the invention is that no form or guide within the tube is required in order to produce the finished product. It will be understood that while'L show only one set of co-operative rolls acting upon thetube, that any desired number thereof may be arranged in multiple to act so that a number of fins may be produced at once by each feeding movement of the rolls, instead of a single fin as herein shown. The described invention may be readily carried out on an ordinary lathe, or any suitable machine of a general lathe type, the essential features being the described co-operative act1on of three or more rolls arranged as described. to work towards the lathe center. The

described operation results in materially condensing and-strengthening the'metal of the tube in producing the described fins by the rolling or spinning operation thereon as set forth. a

I amaware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claim rather than to the foregoing description to indicate the scope of the invention.

Having now described my invention, what and in changing the form 

